In order to display various information, image display devices such as liquid crystal displays have been conventionally used in display devices for vehicle that display information such as a vehicle speed and an engine rotational speed. However, such an image display device displays a planar image which provides less 3D effect and inferior design compared with an image displayed by a mechanical display device. On the other hand, display devices for vehicle have been disclosed, the display devices being capable of providing display with 3D effect by displaying a real image and a virtual image using a mechanical member such as meter and an image display device at the same time.
For example, Japanese Patent No. 5082911 discloses a display device (which corresponds to “the display device for a vehicle” in the claims) that includes a display unit that provides switchable display between a first image and a second image; a light source; a light emitting display member (which corresponds to the “decorative member” in the claims) that has a thickness and receives light emitted from the light source and displays with emission; a plate-shaped member that is disposed between the display unit and the light emitting display member and has a light reflectivity and a light transparency, the plate-shaped member allowing light of one of an image of the display unit and the light emitting display member to pass therethrough to a user's eyes and causing light of the other of the image of the display unit and the light emitting display member to be reflected to a user's eyes; and a control unit that controls the turn-on and turn-off of the light source and displays the first image on the display unit when the light source is turned on and displays the second image on the display unit when the light source is turned off. In the display device, one of the images is displayed as a real image and the other one is displayed as a virtual image. When the light source is turned on, the real image and the virtual image are made close to each other and displayed. The first image includes plural information images, and at least part of the light emitting display member which is turned on is displayed as a boundary image that indicates a boundary between the information images. Japanese Patent No. 5082911 claims that the display device described therein is capable of providing 3D effect to an image of the display unit and of ensuring the flexibility of display by the display unit.
Japanese Unexamined Patent Application Publication (JP-A) No. 7-15424 discloses a display device (which corresponds to “the display device for a vehicle” in the claims) in which a half mirror is provided that intersects with the visual recognition direction of a user, a first display unit is provided in rear of the half mirror, a second display unit is provided in front of the half mirror, display of the first display unit is visually recognizable through the half mirror as a real image, and display of the second display unit is visually recognizable through the half mirror as a virtual image, where the rear surface of the half mirror is provided with a polarizing member that causes transmitted light from the first display unit to be P-wave polarized.
JP-A No. 7-15424 claims that double display is suppressed and clear display is achieved by the display device described therein in which S-wave polarized light in transmitted light from the first display unit is not allowed to enter the half mirror, the S-wave polarized light being likely to be reflected by the half mirror.
However, in the display device described in Japanese Patent No. 5082911, the light emitting display member itself emits light due to the light source, and thus 3D effect on the light emitting display member itself is not visually recognized easily. Therefore, there is room for improvement in design of the display device described in Japanese Patent No. 5082911.
In the display device described in JP-A No. 7-15424, because the first display unit is visually recognizable as a real image all the time, the area where an image from the second display unit is displayed as a virtual image is limited, and thus flexibility in displayable information is low. Therefore, there is room for improvement in ensuring the flexibility of display of the display device described in JP-A No. 7-15424.